Brought an old Woodtek ribbon/combo sander back to life - previously was unable to track the ribbon sanding belt because the hole in this top idler shaft, through which a spring pin goes, was worn open resulting in a lot of play in the setup that shouldn't exist. I was amazed this replacement part existed, and it certainly did the job of fixing that problem. However one issue is the replacement part did not exactly match the old part, some of the axial dimensions were off by a few millimeters, meaning the part would not work without some modification - I drilled out the hole through which the adjustment knob goes, so that it could be assembled without interference. The attached image shows new part (upper) is visibly shorter, necessitating this modification.